It's really interesting/sad to read their second reason for shutting down:
> pro users are more likely to want a larger number of integrations with new services and data sources, something that’s hard to provide with limited revenue, which left the app “close but not quite” for many users
Because this is exactly what Zapier, the company I co-founded a year later, provides for free to other companies/products. Integrate once with us and automatically get integrations with hundreds of other apps (750+ and growing).
I love and use several Panic products (Transmit, Prompt, Firewatch) and hope this end-of-life enables them to spend more time on new ideas.